Systems and methods for reducing pressure at an outflow of a duct

ABSTRACT

Various systems and methods are provided for reducing pressure at an outflow of a duct such as the thoracic duct or the lymphatic duct. In one embodiment, an indwelling catheter can be configured to be at least partially implanted within a vein of a patient in the vicinity of an outflow port of a duct of the lymphatic system. The catheter can include first and second restrictors each configured to at least partially occlude the vein within which the catheter is implanted and thus to restrict fluid flow within the vein when the restrictors are activated. The restrictors can each be configured to move between an activated configuration, in which the restrictor occludes the vein, and a relaxed configuration, in which the restrictor does not occlude the vein. The catheter can include a pump, such as an axial motor pump, configured to pump fluid through the catheter.

CROSS REFERENCE

The present application is a continuation of U.S. patent applicationSer. No. 15/150,637, filed May 10, 2016, which application claimspriority to U.S. Provisional Patent Application No. 62/159,465 entitled“System And Method For Treatment Of Pulmonary Edema” filed May 11, 2015and to U.S. Provisional Patent Application No. 62/233,802 entitled“Systems And Methods For Reducing Pressure At An Outflow Of A Duct”filed Sep. 28, 2015, each of which are hereby incorporated by referencein their entireties.

FIELD

The present disclosure relates generally to systems and methods forreducing pressure at an outflow of a duct.

BACKGROUND

The lymphatic system is part of the circulatory system in conjunctionwith the arterial and venous systems. A primary function of thelymphatic system is to drain excessive interstitial fluid back into thevenous system at two main locations: the thoracic duct and the lymphaticduct, which drain into the left and right subclavian veins,respectively.

Under normal circulatory conditions of the arterial and venous systemsthe interstitial fluid volume balance is maintained and the lymph fluidis cleared back through the lymphatic system. In pathological conditionssuch as Acute Cardiogenic Pulmonary Edema and chronic heart failure, thecapillary hydrostatic pressure and the venous pulmonary pressure canbecome elevated and fluid flows excessively out of the blood vessels andinto the interstitial and alveolar spaces. The pressure gradient betweenthe initial lymphatics and at the outflow of the thoracic duct and thelymphatic duct is reduced and the lymphatic system cannot clear theadditional fluid which accumulates in the air spaces of the lungs. Thisis a life threatening condition as gas exchange is impaired to theextent that it may lead to respiratory failure.

Current treatment methods require extended hospitalization and treatmentwith loop diuretics and/or vasodilators. Oftentimes patients must alsoreceive supplemental oxygen or, in more extreme cases, requiremechanical ventilation. Many of these treatment methods are less thanideal because the edema is not always alleviated rapidly enough and formany patients renal function is adversely affected. A significantpercentage of patients do not respond to this treatment and asignificant percentage must be readmitted to a hospital within thirtydays.

A significant problem with current treatment protocol is that it isbased on the need to reduce intravascular blood pressure to moveinterstitial and lymphatic fluid back into the vasculature. Thereduction of intravascular blood pressure may lead to hypotension andmay activate the Renin Angiotenesin Aldesterone System, which may leadback to an increase in blood pressure or to worsening of renal function.Eventually, this cycle leads to diuretic resistance and the worsening ofrenal function in almost 30% of admitted patients. The lymphatic systemcan directly drain fluids from the interstitial compartment into theintravascular compartment and by such to relief edema.

The lymphatic system drains the interstitial fluids via the thoracicduct and right lymphatic duct that drain into the region around thebifurcation of the left subclavian vein and left internal jugular veinfor the thoracic duct and into the bifurcation of the right internaljugular vein and right subclavian vein for the right lymphatic duct.However, in conditions such as acutely decompensated heart failure thelymphatic return is reduced as a result of elevated central venouspressure (CVP). Therefore, as a result of the elevated CVP, thelymphatic return is greatly reduced.

Accordingly, there remains a need for improved systems and methods forreducing pressure at an outflow of a duct such as the thoracic duct orthe lymphatic duct.

SUMMARY

Various devices, methods, and systems are provided for treating edema.An indwelling catheter configured to be implantable within a vein of apatient is provided that in one embodiment includes a sheath at leastpartially implantable within a patient's vein. The sheath has a lumenextending therethrough and a catheter shaft movably positioned withinand extending through the lumen of the sheath. The indwelling catheteralso includes a catheter shaft movably positioned within and extendingthrough the lumen of the sheath. The catheter shaft is configured to beat least partially implantable within a patient's vein and a proximalend can extend from a proximal end of the sheath and a distal end canextend from a distal end of the sheath. The catheter shaft has a suctionlumen extending therethrough, and one or more suction ports disposedtherein and in fluid communication with the suction lumen. Theindwelling catheter also includes a flexible membrane attached to adistal portion of the catheter shaft. The flexible membrane is acollapsible, tube-like member having a lumen extending therethrough. Theindwelling catheter also includes a selectively deployable restrictionmember formed over a portion of the flexible membrane, and an inflationlumen extending through the catheter shaft. The at least one inflationlumen is in fluid communication with the restriction member.

The indwelling catheter also includes can vary in any number of ways.For example, the indwelling catheter can include a cone shaped tip atthe distal end of the catheter shaft. For another example, the flexiblemembrane can be coupled to an outer wall of the catheter shaft along alength of the flexible membrane. The flexible membrane can be bonded orwelded to the catheter shaft along one or several segments and alongabout 10 to 360 degrees of a circumference of the catheter shaft, e.g.,along about 180 to 270 degrees of a circumference of the catheter shaft.

For yet another example, the flexible membrane can be oriented so as tobe substantially parallel to the catheter shaft. For still anotherexample, the restriction member can be a selectively expandable ballooncoupled to an outer wall of the flexible membrane.

For another example, the indwelling catheter can include a secondselectively deployable restriction member formed over a distal portionof the flexible membrane. The restriction member can be formed over aproximal portion of the flexible membrane, and the at least oneinflation lumen can be in fluid communication with the secondrestriction member. The second selectively deployable restriction membercan be a selectively expandable balloon coupled to an outer wall of theflexible membrane. The indwelling catheter can include a first pressureport disposed proximally of the restriction member, and a secondpressure port disposed between the selectively deployable restrictionmembers. Instead of using pressure ports, a miniature pressure sensorcan be mounted on the catheter at the same locations. For yet anotherexample, the indwelling catheter can include a first pressure portdisposed distally to the second restriction member, and a secondpressure port disposed between the selectively deployable restrictionmembers. Instead of using pressure ports, a miniature pressure sensorcan be mounted on the catheter at the same locations. For anotherexample, the indwelling catheter can include a first pressure portdisposed proximally of the restriction member, a second pressure portdisposed between the selectively deployable restriction members, and athird pressure port disposed distally to the second restriction member.Instead of using pressure ports, a miniature pressure sensor can bemounted on the catheter at the same locations.

For yet another example, the indwelling catheter can include a firstinflation port disposed in an outer wall of the flexible membrane and influid communication with the first selectively deployable restrictionmember. The indwelling catheter can further include a second inflationport disposed on the outer wall of the flexible member and in fluidcommunication with the second selectively deployable restriction member.

In another aspect, a method of treating edema is provided that in oneembodiment includes advancing from a sheath implanted within a vein of apatient a catheter shaft having a flexible and collapsible tubularmembrane coupled to an outer wall of the catheter shaft at a distalportion thereof, so as to position the catheter shaft within the veinsuch that a distal end of the catheter shaft is positioned distally ofat least one outflow port of a duct of the lymphatic system. The methodalso includes actuating a first expandable member attached to themembrane to create a first restriction within the vein adjacent to aproximal region of the flexible membrane of the catheter shaft. Thefirst restriction is positioned proximally of the at least one outflowport. The method also includes actuating a second expandable memberattached to the membrane to create a second restriction within the veindistal to the first restriction and adjacent to a distal region of theflexible membrane of the catheter shaft. The second restriction ispositioned distally of the at least one outflow port. The first andsecond restriction members create a localized low pressure zoneextending therebetween.

The method can have any number of variations. For example, the methodcan include implanting the sheath of the catheter system within the veinof the patient.

For another example, the method can include withdrawing fluid fromwithin the low pressure zone through the catheter to a pump andreturning fluid to a vein such that the returned fluid passes throughthe membrane to bypass the low pressure zone. Withdrawing fluid can beaccomplished by passing fluid from within the low pressure zone througha suction port disposed in a wall of the catheter shaft and in fluidcommunication with the low pressure zone between the first and secondrestrictions. The suction port can be in communication with a suctiontubing line of the catheter to withdraw fluid from the vein through anaction of the pump and return fluid to venous circulation through thesuction tubing line coupled to a proximal end of the catheter sheathwherein the fluid is discharged at a distal end of the catheter sheathproximal to the first restriction. The catheter can be implanted in oneof the right and left internal jugular veins and advanced to a positionsuch that the second restriction is distal to a junction of a subclavianvein and an internal jugular vein, the first restriction can be withinthe internal jugular vein, and the second restriction can be within aninnominate vein and the suction port is adjacent to the junction of thesubclavian vein. The catheter can be implanted in one of the right andleft internal jugular veins and advanced to a position such that thesecond restriction is distal to a junction of a subclavian vein and aninternal jugular vein, and the first restriction can be within theinternal jugular vein, the second restriction can be within aninnominate vein, and the suction port can be adjacent to the junction ofthe subclavian vein. The catheter can be implanted in one of the rightand left internal jugular veins and advanced to a position such that thesecond restriction is distal to a junction of both innominate veins, andthe first restriction can be within the internal jugular vein, thesecond restriction can be within a superior vena cava (SVC) vein (alsoreferred to as an innominate vein), and the suction port can be adjacentto a junction of the subclavian vein.

For yet another example, transporting the fluid through the localizedlow pressure zone via the flexible membrane can maintain a constantpressure within the low pressure zone.

In another aspect, a system for treating edema is provided that in oneembodiment includes an indwelling catheter system configured for atleast partial placement within a vein of a patient. The indwellingcatheter system has an implantable sheath with a lumen extendingtherethrough, and a catheter shaft movably positioned within andextending through the lumen of the sheath. The catheter shaft has one ormore suction ports disposed therein. The indwelling catheter system alsohas a flexible membrane attached to a distal portion of the cathetershaft, a first selectively deployable restriction member formed over aproximal portion of the flexible membrane, and a second selectivelydeployable restriction member formed over a distal portion of theflexible membrane and an inflation lumen extending through the cathetershaft. The inflation lumen is in fluid communication with the first andthe second restriction members. The system for treating edema furtherincludes a pump configured to create a pressure differential to withdrawfluid from the suction port and through a suction lumen from thecatheter shaft to withdraw a fluid within the vein from venouscirculation and to return the fluid to venous circulation through thecatheter system, a plurality of pressure sensors disposed within thecatheter system, and a control module configured to control operation ofthe system.

The system for treating edema can have any number of variations. Forexample, the system for treating edema can include a pump configured tobe external to the patient. For another example, the pump can be aperistaltic flow pump.

Various systems and methods are provided for reducing pressure at anoutflow of a duct such as the thoracic duct or the lymphatic duct. Amedical system is provided that in one embodiment includes a cathetershaft configured to be positioned within a vein of a patient, a firstselectively deployable restrictor coupled to the catheter shaft andconfigured to be positioned within the vein, a second selectivelydeployable restrictor coupled to the catheter shaft at a location distalto the first restrictor such that a distance spans between the first andsecond restrictors, at least one inlet opening formed through a sidewallof the catheter shaft at a location between the first and secondrestrictors, and a pump configured to facilitate suction of fluid intothe catheter shaft through the at least one inlet opening. The secondrestrictor is configured to be positioned within the vein.

The medical system can have any number of variations. For example, thefirst and second restrictors can each include a balloon. The medicalsystem can include at least one inflation lumen extending along thecatheter shaft. The at least one inflation lumen can be in fluidcommunication with the first and second restrictors. The at least oneinflation lumen can include a single lumen in fluid communication withboth of the first and second restrictors, or the at least one inflationlumen can include a first inflation lumen in fluid communication withthe first restrictor and a second inflation lumen in fluid communicationwith the second restrictor.

For another example, the first restrictor can be movable between anactivated configuration in which the first restrictor has a firstdiameter and a relaxed configuration in which the first restrictor has asecond diameter that is less than the first diameter, and the secondrestrictor can be movable between an activated configuration in whichthe second restrictor has a third diameter and a relaxed configurationin which the second restrictor has a fourth diameter that is less thanthe third diameter. The first diameter can be equal to the thirddiameter, or the first diameter can be less than the third diameter.

For yet another example, the first and second restrictors can eachinclude a stent. For still another example, the medical system caninclude at least one additional inlet opening formed through thesidewall of the catheter shaft at a location that is proximal to thefirst and second restrictors. For another example, the catheter shaftcan have an open distal end. For yet another example, the pump caninclude an impeller within the catheter shaft. For another example, thepump can be configured to be positioned within the vein, or the pump canbe non-implantable. For still another example, the medical system caninclude at least one sensor.

For another example, the medical system can include a controllerconfigured to actuate the pump. The controller can be configured toactuate the pump in response to user operation of a control external tothe body of the patient. The medical system can include a pressuresensor configured to be implanted in the body of the patient, and thecontroller can be configured to actuate the pump in response to apressure measured by the pressure sensor exceeding a predefinedthreshold and/or the controller can be configured to control a speed ofoperation of the pump depending on a pressure measured by the pressuresensor.

For yet another example, the medical system can include a flexiblemembrane attached to a distal portion of the catheter shaft. Theflexible membrane can be a collapsible, tube-like member having a lumenextending therethrough. The first and second restrictor can each beformed over a portion of the flexible membrane.

For another example, the vein can include an internal jugular vein or asubclavian vein.

In another aspect, a medical method is provided that can includeimplanting the catheter shaft at least at least partially within a veinof a patient such that the first restrictor is positioned upstream of anoutflow port of a duct of the patient's lymphatic system and such thatthe second restrictor is positioned downstream of the outflow port ofthe duct.

The medical method can vary in any number of ways. For example, themedical method can include activating the first restrictor of themedical system such that the first restrictor occludes the vein at afirst occlusion site, and activating the second restrictor such that thesecond restrictor occludes the vein at a second occlusion site.Activating the first restrictor can include inflating the firstrestrictor, and activating the second restrictor can include inflatingthe second restrictor, and/or activating the first restrictor caninclude radially expanding the first restrictor, and activating thesecond restrictor can include radially expanding the second restrictor.For another example, the medical method can include actuating the pump,thereby creating a low pressure zone between the first and secondrestrictors. For yet another example, the duct can include a thoracicduct. For still another example, the duct can include a lymphatic duct.For another example, the vein can include an internal jugular vein or asubclavian vein.

In another embodiment, a medical system is provided that includes acatheter shaft configured to be positioned within a vein of a patient,and at least one restrictor coupled to the catheter shaft and configuredto be positioned within the vein. The at least one restrictor is movablebetween an activated configuration in which the at least one restrictorhas a first diameter and a relaxed configuration in which the at leastone restrictor has a second diameter that is less than the firstdiameter. The at least one restrictor is configured to occlude fluidflow through the vein when the at least one restrictor is in theactivated configuration within the vein. The medical system alsoincludes a pump configured to pump fluid through the catheter shaftregardless of whether the at least one restrictor is in the activatedconfiguration or the relaxed configuration.

The medical system can have any number of variations. For example, theat least one restrictor includes a single restrictor. For anotherexample, the at least one restrictor can include first and secondrestrictors. The second restrictor can be coupled to the catheter shaftat a location distal to the first restrictor such that a distance spansbetween the first and second restrictors.

For yet another example, the at least one restrictor can include aballoon. The medical system can include at least one inflation lumenextending along the catheter shaft. The at least one inflation lumen canbe in fluid communication with the at least one restrictor.

For still another example, the at least one restrictor can include astent. For yet another example, the pump can include an impeller withinthe catheter shaft. For another example, the pump can be configured tobe positioned within the vein, or the pump can be non-implantable. Forstill another example, the medical system can include at least onesensor.

For yet another example, the medical system can include a controllerconfigured to actuate the pump. The controller can be configured toactuate the pump in response to user operation of a control external tothe body of the patient. The medical system can include a pressuresensor configured to be implanted in the body of the patient, and thecontroller can be configured to actuate the pump in response to apressure measured by the pressure sensor exceeding a predefinedthreshold and/or can be configured to control a speed of operation ofthe pump depending on a pressure measured by the pressure sensor.

For still another example, the medical system can include a flexiblemembrane attached to a distal portion of the catheter shaft. Theflexible membrane can be a collapsible, tube-like member having a lumenextending therethrough. The at least one restrictor can be formed over aportion of the flexible membrane.

For another example, the vein can include an internal jugular vein or asubclavian vein.

In another aspect, a medical method is provided that includes implantingthe catheter shaft of the medical system at least at least partiallywithin a vein of a patient such that the at least one restrictor ispositioned upstream of an outflow port of a duct of the patient'slymphatic system.

The medical method can have any number of variations. For example, themedical method can include activating the at least one restrictor suchthat the at least one restrictor occludes the vein. Activating the atleast one restrictor can include inflating the at least one restrictorand/or radially expanding the at least one restrictor.

For another example, the medical method can include actuating the pump,thereby creating a low pressure zone adjacent the duct. For yet anotherexample, the duct can include a thoracic duct. For still anotherexample, the duct can include a lymphatic duct. For another example, thevein can include an internal jugular vein or a subclavian vein.

In another embodiment, a medical method is provided that includes atleast partially implanting a catheter shaft within a vein of a patient,thereby positioning a first restrictor coupled to the catheter shaft ata location that is upstream of an outflow port of a duct of thepatient's lymphatic system and positioning a second restrictor coupledto the catheter shaft at a location that is downstream of the outflowport of the duct. The catheter shaft has a pump coupled thereto. Themedical method also includes, after the first restrictor is positioned,actuating the first restrictor to move the first restrictor from arelaxed configuration to an activated configuration. The medical methodalso includes, after the second restrictor is positioned, actuating thesecond restrictor to move the second restrictor from a relaxedconfiguration to an activated configuration. The medical method alsoincludes, after the first and second restrictors are actuated, actuatingthe pump to cause a low pressure zone to be created along the catheterbetween the first and second restrictors.

The medical method can vary in any number of ways. For example,actuating the first restrictor can include inflating the firstrestrictor, and actuating the second restrictor can include inflatingthe second restrictor. For another example, actuating the firstrestrictor can include radially expanding the first restrictor, andactuating the second restrictor can include radially expanding thesecond restrictor. For yet another example, the medical method caninclude, after the pump is actuated, re-actuating the first restrictorto move the first restrictor from the activated configuration to therelaxed configuration, and re-actuating the second restrictor to movethe second restrictor from the activated configuration to the relaxedconfiguration. After re-actuating the first and second restrictors, thecatheter shaft and the first and second restrictors can be removed fromthe patient.

For still another example, the pump can be actuated in response to useroperation of a control external to the body of the patient. For anotherexample, the pump can be actuated periodically or continuously. For yetanother example, the duct can include a thoracic duct of the patient.For still another example, the duct can include a lymphatic duct of thepatient. For another example, the vein can include an internal jugularvein of the patient or a subclavian vein of the patient.

For yet another example, the medical method can include implanting apressure sensor in a location within the body of the patient thatenables the pressure sensor to measure pressure in a desired region ofthe body of the patient. The medical method can include measuring thepressure in the desired region using the pressure sensor, and actuatingthe pump in response to the measured pressure exceeding a predefinedthreshold and/or controlling a speed of operation of the pump dependingon the measured pressure.

BRIEF DESCRIPTION OF DRAWINGS

This invention will be more fully understood from the following detaileddescription taken in conjunction with the accompanying drawings, inwhich:

FIG. 1 is a schematic cross-sectional view of one embodiment of acatheter implanted in a vein of a patient;

FIG. 2 is a perspective, partially transparent view of a distal portionof another embodiment of a catheter;

FIG. 3 is a perspective, partially transparent view of a distal portionof yet another embodiment of a catheter;

FIG. 4 is a partial cross-sectional view of the distal portion of thecatheter of FIG. 3;

FIG. 5 is a cross-sectional view of the distal portion of the catheterof FIG. 3;

FIG. 6 is a schematic version of the cross-sectional view of FIG. 5;

FIG. 7 is a perspective, partially transparent view of a distal portionof yet another embodiment of a catheter;

FIG. 8 is a partial cross-sectional view of the distal portion of thecatheter of FIG. 7;

FIG. 9 is a schematic version of the cross-sectional view of FIG. 8;

FIG. 10 is a perspective view of one embodiment of a catheter system;

FIG. 10A is perspective view of a flexible membrane and catheter shaftof the catheter system of FIG. 10;

FIG. 10B is another perspective view of the flexible membrane andcatheter shaft of the catheter system of FIG. 10A;

FIG. 10C is a perspective view of a restrictor of the catheter system ofFIG. 10 attached to the flexible membrane of the catheter system;

FIG. 10D is side, partial cross-sectional view of flattened edges of therestrictor of FIG. 10A;

FIG. 10E is a side, partial cross-sectional view of folded edges ofanother embodiment of a restrictor;

FIG. 10F is a cross-sectional schematic view of one embodiment of apattern for forming a restriction member with a torus shape;

FIG. 10G is cross-sectional schematic view of one embodiment of arestriction member formed using the pattern of FIG. 10F and oneembodiment of a sleeve on which the restriction member is assembled;

FIG. 10H is a cross-sectional schematic view of the restriction memberof FIG. 10G following inversion of legs thereof;

FIG. 11A is a perspective view of a distal portion of the cathetersystem of FIG. 10;

FIG. 11B is a side view of another distal portion of the catheter systemof FIG. 10;

FIG. 12A is a perspective view of a proximal portion of the cathetersystem of FIG. 10;

FIG. 12B is a side view of the catheter system of FIG. 10;

FIG. 13 is a distal end view of the catheter system of FIG. 10;

FIG. 14 is a cross sectional view of the catheter system of FIG. 10 witha flexible membrane of the catheter system in an expanded configuration;

FIG. 15 is a cross sectional view of the catheter system of FIG. 10having a restrictor thereof in an activated configuration;

FIG. 16 is a cross sectional view of the catheter system of FIG. 10having a restrictor thereof in a relaxed configuration;

FIG. 17A is a schematic, partially cross-sectional view of a portion ofthe catheter system of FIG. 10 implanted in a patient;

FIG. 17B is a perspective, partially cross-sectional view of anotherportion of the catheter system of FIG. 17A implanted in the patient;

FIG. 17C is another perspective, partially cross-sectional view of thecatheter system of FIG. 17A implanted in the patient;

FIG. 18 is a side cross-sectional view of a distal portion of thecatheter system of FIG. 10;

FIG. 19 is a cross-sectional view of the distal portion of the cathetersystem of FIG. 18;

FIG. 20 is a schematic, partially cross-sectional view of a distalportion of the catheter system of FIG. 10 introduced into a vein;

FIG. 21 is a schematic diagram of one embodiment of a control module;

FIG. 22 is a front view of one embodiment of the control module of FIG.21;

FIG. 23 is a perspective partially cross-sectional view of a distalportion of one embodiment of a catheter system advanced into a body of apatient;

FIG. 24 is a perspective partially cross-sectional view of a catheter ofthe catheter system of FIG. 23 advanced distally out of a sheath of thecatheter system with restrictors of the catheter being in a collapsedconfiguration;

FIG. 25 is a perspective partially cross-sectional view of the sheathand catheter of FIG. 24 with the restrictors in an expandedconfiguration;

FIG. 26 is a perspective partially cross-sectional view of the catheterof FIG. 25 with a pump of the catheter system suctioning blood throughthe catheter;

FIG. 26A is side partially cross-sectional view of the catheter of FIG.26;

FIG. 27 is a perspective partially cross-sectional view of the catheterof FIG. 26 with the pump of the catheter system suctioning blood throughthe catheter and discharging blood into the sheath;

FIG. 28 is a perspective partially cross-sectional view of the catheterof FIG. 27; and

FIG. 29 is a flow diagram for one embodiment of operation of a controlmodule for a system of treating edema.

DETAILED DESCRIPTION

Certain exemplary embodiments will now be described to provide anoverall understanding of the principles of the structure, function,manufacture, and use of the devices and methods disclosed herein. One ormore examples of these embodiments are illustrated in the accompanyingdrawings. Those skilled in the art will understand that the devices andmethods specifically described herein and illustrated in theaccompanying drawings are non-limiting exemplary embodiments and thatthe scope of the present invention is defined solely by the claims. Thefeatures illustrated or described in connection with one exemplaryembodiment may be combined with the features of other embodiments. Suchmodifications and variations are intended to be included within thescope of the present invention.

Reference throughout the specification to “various embodiments,” “someembodiments,” “one embodiment,” or “an embodiment,” or the like, meansthat a particular feature, structure, or characteristic described inconnection with the embodiment is included in at least one embodiment.Thus, appearances of the phrases “in various embodiments,” “in someembodiments,” “in one embodiment,” or “in an embodiment,” or the like,in places throughout the specification are not necessarily all referringto the same embodiment. Furthermore, the particular features,structures, or characteristics may be combined in any suitable manner inone or more embodiments. Thus, the particular features, structures, orcharacteristics illustrated or described in connection with oneembodiment may be combined, in whole or in part, with the featuresstructures, or characteristics of one or more other embodiments withoutlimitation.

It will be appreciated that the terms “proximal” and “distal” may beused throughout the specification with reference to a clinicianmanipulating one end of an instrument used to treat a patient. The term“proximal” refers to the portion of the instrument closest to theclinician and the term “distal” refers to the portion located furthestfrom the clinician. It will be further appreciated that for concisenessand clarity, spatial terms such as “vertical,” “horizontal,” “up,” and“down” may be used herein with respect to the illustrated embodiments.However, surgical instruments may be used in many orientations andpositions, and these terms are not intended to be limiting and absolute.

Further, in the present disclosure, like-named components of theembodiments generally have similar features, and thus within aparticular embodiment each feature of each like-named component is notnecessarily fully elaborated upon. Additionally, to the extent thatlinear or circular dimensions are used in the description of thedisclosed systems, devices, and methods, such dimensions are notintended to limit the types of shapes that can be used in conjunctionwith such systems, devices, and methods. A person skilled in the artwill recognize that an equivalent to such linear and circular dimensionscan easily be determined for any geometric shape. Sizes and shapes ofthe systems and devices, and the components thereof, can depend at leaston the anatomy of the subject in which the systems and devices will beused, the size and shape of components with which the systems anddevices will be used, and the methods and procedures in which thesystems and devices will be used.

Various systems and methods are provided for reducing pressure at anoutflow of a duct such as the thoracic duct or the lymphatic duct. Ingeneral, the systems and methods may be effective to reduce edemaconditions, such as pulmonary edema, in a patient by lowering an outflowpressure in a region around the patient's thoracic/lymphatic ductoutflow. As a result of lowering the outflow pressure at the thoracicand/or lymphatic ducts, higher lymphatic return will be achieved,enabling the lymphatic vessel flow to be at or near normal levels. Thesystems and methods may be effective to rapidly alleviate conditions ofthe edema and increase the patient response rate. In an exemplaryembodiment, the systems and methods may be particularly useful to treatacute pulmonary edema, however a person skilled in the art willappreciate that the systems and methods can be used in variousprocedures for treating a lymphatic system fluid clearance imbalance.

In one embodiment, an indwelling catheter can be configured to be atleast partially implanted (e.g., partially implanted or fully implanted)within a vein of a patient in the vicinity of an outflow port of a ductof the lymphatic system, e.g., in the vicinity of an outflow port of thethoracic duct or in the vicinity of an outflow port of the lymphaticduct. Exemplary materials from which the catheter can be made includepolyurethanes. The catheter can include first and second restrictors(also referred to herein as “restriction members”) each configured to atleast partially occlude the vein within which the catheter is implantedand thus to restrict fluid flow within the vein when the restrictors areactivated. The restrictors can each be configured to move between anactivated configuration, in which the restrictor occludes the vein, anda relaxed configuration, in which the restrictor does not occlude thevein. The restrictors can each be in the relaxed configuration duringimplantation of the catheter to ease introduction of the catheter intothe patient's body and into the vein. Each of the restrictors caninclude a balloon configured to be inflated where in the relaxedconfiguration the balloon is not inflated and in the activatedconfiguration in which the balloon is inflated. The restrictors can bemade from any one or more of a variety of materials configured to expandupon the delivery of a fluid thereto and to contract upon the withdrawalof the fluid. Exemplary materials from which the balloon can be madeinclude polymeric materials such as PEBAX, silicones, polyurethanes, andnylons. The catheter can include at least one inflation lumen throughwhich an inflation fluid (e.g., air, liquid, etc.) can be introduced toinflate/deflate the restrictors. The at least one inflation lumen caninclude one lumen in fluid communication with both of the restrictorssuch that the restrictors can be simultaneously inflated/deflated, orcan include first and second lumens with the first lumen in fluidcommunication with the first restrictor and the second lumen in fluidcommunication with the second restrictor such that the restrictors canbe selectively inflated simultaneously or sequentially. The catheter caninclude a pump, such as an axial motor pump, configured to pump fluidthrough the catheter. The catheter can be coupled to a motor configuredto drive the pump. The motor can be included in the catheter (e.g.,within a shaft of the catheter) and be configured to be implanted withthe catheter, or the motor can be located outside of the catheter (e.g.,outside of the catheter's shaft) and be configured to be located outsideof the patient rather than be implanted therein.

In one embodiment of using the catheter, the catheter can be positionedat a desired location within the vein. The first and second restrictorscan then each be activated (simultaneously or sequentially) to move fromthe relaxed configuration to the activated configuration. The first andthe second restrictors, when activated so as to provide two occlusionswithin the vein, define a low pressure zone therebetween within aportion of the vein in which the catheter is positioned. Higher pressurezones accordingly exist on either side of the restrictors. The motor candrive the pump to induce the low pressure zone by causing fluid to bepumped through the catheter. The catheter and the restrictors can bepositioned within the vein such that the low pressure zone is adjacentto an outflow port of a duct (e.g., the thoracic duct or the lymphaticduct) to allow fluid to pass from the lymph duct outflow port to theportion of the catheter housed within the vein so that fluid can flowout of the catheter.

In at least some embodiments, the restrictor(s) of a catheter can beinflated and deflated from time to time to enable free flow of blood ina patient's vein in which the restrictor(s) are positioned and thusenable the system to stop working for a period of time. This period oftime can be required in such treatments to allow for the assessment ofthe patient's clinical condition, allow the patient to undergo othertreatments or enable him to go to the bathroom and/or to wash anystagnation points that might have occurred.

The catheters described herein can be configured to be placed in apatient's body for up to about seventy-two hours, e.g., the catheter canbe indwelled in the body for up to about seventy-two hours. The cathetersystems described herein that include the catheters can be operated in atreatment time period in a range of about 6 to 8 hours. At the end ofeach treatment period, the restrictors are deflated, the catheter can befilled with a heparin catheter locking solution, and an assessment ofthe patient's clinical condition can be performed. The catheter systemcan be operated again if desired by medical personnel. Within theindwelling period of the catheter, a number of treatment periods can bein a range of 3 to 6 cycles, e.g., for a maximum of about forty hours ofoperation within a seventy-two hour indwelling period.

A person skilled in the art will appreciate that the systems and methodsdisclosed herein can be used with a variety of surgical devices,including measuring devices, sensing devices, locator devices, insertiondevices, etc.

FIG. 1 illustrates one embodiment of a catheter 1 that includes at leastone restrictor 2 a, 2 b. The at least one restrictor includes first andsecond restrictors 2 a, 2 b in this illustrated embodiment, which eachinclude a balloon configured to be inflated (corresponding to anactivated configuration) and deflated (corresponding to a relaxedconfiguration). The first and second restrictors 2 a, 2 b can be spaceda distance apart from one another along a longitudinal length of thecatheter 1 such that one of the restrictors 2 b is more distal than theother of the restrictors 2 a. The distance between the first and secondrestrictors 2 a, 2 b can define a length of a low pressure zone that canbe created when the catheter 1 is implanted within a vein. FIG. 1 showsthe catheter 1 positioned within an internal jugular vein 3 of a patientwith the distal restrictor 2 b positioned distal to an outflow port 4 pof the patient's thoracic duct 4 and the proximal restrictor 2 apositioned proximal to the outflow port 4 p of the patient's thoracicduct 4. The low pressure zone defined between the proximal and distal(first and second) restrictors 2 a, 2 b can thus be located adjacent theoutflow port 4 p of the thoracic duct 4. The proximal restrictor 2 abeing positioned proximal to (e.g., upstream) of the outflow port 4 p ofthe thoracic duct 4 may help prevent back flow from the patient'ssubclavian vein 5 while providing the low pressure zone and benefit(s)thereof. The catheter 1 can be similarly positioned on a right side ofthe patient with the distal restrictor 2 b positioned distal to anoutflow port of the patient's subclavian vein 5 and an outflow port ofthe patient's lymphatic duct (not shown) and the proximal restrictor 2 apositioned proximal to the outflow port of the patient's subclavian vein5 and the outflow port of the patient's lymphatic duct.

The catheter 1 can include at least one inflation lumen (omitted fromFIG. 1 for clarity of illustration) configured to facilitate inflationof the first and second restrictors 2 a, 2 b, e.g., to facilitatemovement of the restrictors 2 a, 2 b between the activated and relaxedconfigurations. The first and second restrictors 2 a, 2 b are shown inthe activated configuration in FIG. 1 with the first and secondrestrictors 2 a, 2 b each abutting an internal surface of the jugularvein 3 so as to provide two, spaced-apart occlusions therein.

The catheter 1 can include a shaft 7 having a lumen 7L, as shown in thisillustrated embodiment, configured to communicate fluid therethrough soas to accommodate the flow of fluid in a vein in which the catheter 1 isimplanted. The shaft 7 can have a variety of sizes, such as having adiameter that is in the range of about 8 to 18 Fr (e.g., about 8 Fr,equal to or less than about 12 Fr, etc.) and having a length in therange of about 25 to 40 cm.

The first and second restrictors 2 a, 2 b can be attached to andsurround the shaft 7. The first and second restrictors 2 a, 2 b can eachbe formed in the shape of a torus, as in this illustrated embodiment, tofacilitate the surrounding of the shaft 1 and/or to help preventcompression of the restrictors 2 a, 2 b when they are moved radiallyoutward during expansion thereof and thereby thus overcoming a possibletendency for the restrictors 2 a, 2 b to collapse in response to anexternal pressure. The first and second restrictors 2 a, 2 b can,however, have other shapes.

The catheter 1 can have a first or distal suction inlet 8 d formedthrough the shaft's sidewall. The distal suction inlet can be incommunication with the lumen 7L so as to allow fluid to enter the lumen7L therethrough, as shown in FIG. 1 by four arrows at the distal suctioninlet 8 d pointing inward toward the lumen 7L. The distal suction inlet8 d can include any number of openings formed through the shaft'ssidewall. The openings can have any of a variety of configurations,e.g., slits, circular holes, ovular holes, rectangular slots, etc. Thedistal suction inlet 8 d can be located along the catheter'slongitudinal length at a position between the first and secondrestrictors 2 a, 2 b. The distal suction inlet 8 d can thus be locatedwithin the low pressure zone. In an exemplary embodiment, as shown inFIG. 1, in use, the distal suction inlet 8 d can be positioned adjacentthe outflow ports 4 p, 5 p of the thoracic duct 4 and the subclavianvein 5 so as to allow fluid exiting the outflow ports 4 p, 5 p to enterthe catheter 1.

The catheter 1 can include a second or proximal suction inlet 8 p formedthrough the shaft's sidewall. The proximal suction inlet 8 p can be incommunication with the lumen 7L so as to allow fluid to enter thecatheter's lumen 7L therethrough, as shown in FIG. 1 by two arrows atthe proximal suction inlet 8 p pointing inward toward the lumen 7L. Theproximal suction inlet 8 p can include any number of openings formedthrough the shaft's sidewall. The openings can have any of a variety ofconfigurations, e.g., slits, circular holes, ovular holes, rectangularslots, etc. The proximal suction inlet 8 p can be located proximal tothe distal suction inlet 8 d and proximal to the first and secondrestrictors 2 a, 2 b. In an exemplary embodiment, as shown in FIG. 1, inuse, the proximal suction inlet 8 p can be positioned proximal to theoutflow ports 4 p, 5 p of the thoracic duct 4 and the subclavian vein 5,e.g., upstream thereof. The proximal suction inlet 8 p may thus allowfor regular fluid flow through the jugular vein 3 even when the proximalrestrictor 2 a is activated and occluding the jugular vein 3.

The catheter 1 can include a distal end 1 d configured to be implantedwithin the patient's body (e.g., within the jugular vein 3, as shown inthis illustrated embodiment) and a proximal end 1 p configured to not beimplanted and instead be located outside the patient's body when thecatheter's distal end 1 d is implanted. The distal end 1 d of thecatheter 1 can be open so as to define a discharge opening of thecatheter 1 that allows fluid in the lumen 7L to exit the catheter 1therethrough. The distal restrictor 2 b being positioned proximal to thedischarge opening may help prevent back flow of fluid exiting thecatheter 1 through the discharge opening. The distal restrictor 2 b canthus be positioned just proximal to the discharge opening to helpmaximize backflow prevention. The catheter's proximal end 1 p isconfigured to not be implanted and is shown outside of the patient'sbody in FIG. 1. FIG. 1 also shows a controller or motor 9 coupled to thecatheter 1 and located outside of and proximal to the catheter'sproximal end 1 p so as to not be within the catheter's shaft 7 and to belocated outside of the patient's body. Alternatively, as mentionedabove, the catheter's proximal end 1 p can be configured to beimplanted, such as when the controller or motor 9 is included in thecatheter's shaft 7.

The catheter 1 can include a pump configured to drive fluid flow throughthe catheter 1, e.g., through the lumen 7L thereof. The pump can have avariety of configurations. As in this illustrated embodiment, the pumpcan include an axial motor pump. The axial motor pump can generally beconfigured like an Archimedes' screw that drives fluid. The axial motorpump can include an impeller I and a drive shaft S (e.g., a cable or arod) each located in the catheter's shaft 7, e.g., in the lumen 7L. Alsoas in this illustrated embodiment, the impeller I can be located fullydistal to the proximal restrictor 2 a and can be located at leastpartially proximal to the second restrictor 2 b so as to be at leastpartially located within the low pressure zone and hence near the distalinlet opening. In this illustrated embodiment, the impeller I is fullylocated within the low pressure zone. The drive shaft S can extendlongitudinally through the catheter 1, e.g., through the lumen 7L, tothe controller or motor 9. The motor 9 can be configured to drive thedrive shaft S, e.g., to rotate the drive shaft S, and hence drive theimpeller I, e.g., rotate the impeller I. The drive shaft S can be asolid member, which may provide structural stability to the drive shaftS. Alternatively, the drive shaft S can be hollow, e.g., be cannulated.The drive shaft S being hollow can allow a guide wire to be advancedtherethrough, which may facilitate delivery of the catheter 1 into avein, as will be appreciated by a person skilled in the art, such as byallowing the guide wire to be introduced into a vein and the catheter 20to then be advanced over the guide wire (and into a sheath (not shown)of the system 10 advanced over the guide wire prior to the catheter 20being advanced over the guide wire, if the system 10 includes a sheath).For example, the guide wire can be introduced into the jugular vein 3(e.g., a Seldinger technique via a central venous access underultrasound guidance), and then the drive shaft S (and the catheter 1coupled thereto) can be advanced over the guide wire into the jugularvein 3.

The pump can be configured to pump fluid at a variety of rates. In anexemplary embodiment, the pump can be configured to pump fluid at a ratein a range of about 100 to 1000 ml/hour, which can provide a pressurereduction in the low pressure zone from a pressure in a range of about10 to 20 mmHg (the pressure in the higher pressure zones) to a pressurein a range of about 0 to 6 mmHg (e.g., in a range of about 2 to 4 mmHg,which is a typical normal level, or in a range of about 2 to 5 mmHg,which is also a typical normal level). In at least some embodiments, thepump can have a static, e.g., unchangeable, flow rate. The flow rate canthus be predictable and/or chosen for a specific patient. In otherembodiments, the pump can have an adjustable flow rate. The flow ratebeing adjustable can help the pump accommodate changes in the patient'scondition over time and/or allow the pump to be driven at a selectedrate for a particular patient. The flow rate can be adjustable in avariety of ways, as will be appreciated by a person skilled in the art,such as by being wirelessly adjusted using a user-operated controldevice located external to the patient and configured to wirelesslycommunicate with the pump (e.g., with the controller 9) to adjust theflow rate thereof.

In at least some embodiments, the controller 9 can be configured to bein electronic communication with at least one pressure sensor (notshown). A person skilled in the art will appreciate that a variety ofsuitable sensors can be used for monitoring pressure, such as centralvenous pressure (CVP) or other fluid pressure sensors, and bloodpressure sensors. The at least one pressure sensor can be implanted inthe patient as part of the pump, implanted in the patient as a separatecomponent from the pump, or the at least one pressure sensor can belocated external to the patient, such as by being on a skin surfacethereof. If not already a part of the pump so as to be in electroniccommunication therewith, the at least one pressure sensor can beconfigured to be in electronic communication with the pump over acommunication line such as a wired line or a wireless line. In anexemplary embodiment, two pressure sensors can be implanted in thepatient. One of the pressure sensors can be implanted between the firstand second restrictors 2 a, 2 b so as to be in the low pressure zone,and the other one of the pressure sensors can be implanted in the veineither proximal to the proximal restrictor 2 a (e.g., proximal to theproximal inlet) or distal to the distal restrictor 2 b (e.g., distal tothe discharge opening) so as to be in one of the higher pressure zones.The two sensors can thus allow a pressure differential to be determinedbetween the low pressure zone and the higher pressure zone. In otherembodiments, another number of pressure sensors can be implanted in thepatient (e.g., one, three, four etc.) and/or the pressure sensor(s) canbe implanted at other locations.

The catheter 1 can include at least one lumen (not shown) configured tofacilitate use of the pressure sensor(s), for example to facilitateplacement of the pressure sensor(s) and/or to be filled with a fluidsuch as saline to allow for external pressure measurement.

In addition to or instead of the one or more pressure sensors, thecontroller 9 can be configured to be in electronic communication with atleast one other type of sensor (not shown) configured to sense aparameter other than pressure. Examples of sensors that can be used tomeasure a parameter other than pressure include radio frequencytransmitters and receivers, fluid sensors, bioimpedance sensors, heartrate sensors, breathing sensors, activity sensors, and optical sensors.Examples of the measured parameter include fluid amount (e.g., asmeasured by a fluid sensor, such as a fluid sensor placed in a lung tosense fluid amount in the lung), bioimpedance (e.g., as measured by abioimpedance sensor), heart rate (e.g., as measured by a heart ratesensor), breathing rate (e.g., as measured by a breathing sensor),patient activity level (e.g., as measured by an activity sensor), andorgan dimension (e.g., as measured by an optical sensor). The sensor canbe implanted in the patient as part of the pump, implanted in thepatient as a separate component from the pump (e.g., implanted in aninterstitial space around a lung, implanted at a junction of a rightsubclavian vein of a patient and an internal jugular vein of thepatient, implanted at a junction of a left subclavian vein of a patientand an internal jugular vein of the patient, etc.), or the sensor can belocated external to the patient, such as by being on a skin surfacethereof. If not already a part of the pump so as to be in electroniccommunication therewith, the non-pressure sensor(s) can be configured tobe in electronic communication with the pump over a communication linesuch as a wired line or a wireless line. The non-pressure sensor(s) caninclude one or more sensors. In embodiments including a plurality ofsensors, each of the sensors can be configured to measure the sameparameter as or a different parameter than any one or more of the othersensors.

The motor 9 can be included as part of the pump and can be configured tobe implanted in the patient with the pump, or, as in this illustratedembodiment, the motor 9 can be configured to be non-implantable. Themotor 9 being non-implantable can help the pump have a smaller sizeand/or can allow the pump to be driven by a more powerful motor sincethe motor 9 can be larger than an implantable motor.

The controller 9 can be included as part of the pump and can beconfigured to be implanted in the patient with the pump, or, as in thisillustrated embodiment, the controller 9 can be configured to benon-implantable. The controller 9 being part of the pump can help allowthe pump to be a self-contained system, although in such a controllerrequires space in the pump, which can increase a size of the pump. Thecontroller 9 being non-implantable can help the pump have a smaller sizeand/or can allow the pump to be controlled by a more powerful processorsince the processor can be more easily upgraded than if implanted withthe pump and/or since the processor's size can be less important whenoutside the pump as opposed to inside the pump.

The controller 9 can include any type of microprocessor or centralprocessing unit (CPU), including programmable general-purpose orspecial-purpose microprocessors and/or any one of a variety ofproprietary or commercially available single or multi-processor systems.The controller 9 can be a component of a control system that includesany number of additional components, such as a memory configured to canprovide temporary storage and/or non-volatile storage; a bus system; anetwork interface configured to enable the control system to communicatewith other devices, e.g., other control systems, over a network; and aninput/output (I/O) interface configured to connect the control systemwith other electronic equipment such as I/O devices (e.g., a keyboard, amouse, a touchscreen, a monitor, etc.) configured to receive an inputfrom a user.

The controller 9 can be configured to receive user input thereto tocontrol any of a variety of aspects related to the catheter 1, such asspeed of the motor 9 and ideal range of pressure for the low pressurezone.

In at least some embodiments, the pump can be configured to change itspumping rate (e.g., from zero to a non-zero value, from a non-zero valueto zero, or from one non-zero value to another non-zero value) based onpressure measured by the at least one pressure sensor. The controller 9can be configured to effect such change in response to the sensedpressure. If the measured pressure exceeds a predetermined thresholdmaximum pressure value, the pump can be configured to increase its pumprate (e.g., increase from zero or increase from some non-zero value) inan effort to decrease the pressure. For example, if the measuredpressure within the low pressure zone is too high (e.g., is above apredetermined threshold), the pump can increase its pump rate todecrease the pressure within the low pressure zone. For another example,if the measured pressure within the low pressure zone is below apredetermined threshold, the pump can decrease its pump rate to maintainor increase the pressure within the low pressure zone. For yet anotherexample, if a measured pressure differential between the low pressurezone and the higher pressure zone is not sufficiently great (e.g., isbelow a predetermined threshold), the pump can increase its pump rate toincrease the pressure differential.

In at least some embodiments, the catheter 1 can include only onerestrictor, the proximal restrictor 2 a. A higher pressure zone can thusbe proximal to the proximal restrictor, and a low pressure zone can bedistal to the proximal restrictor. The proximal restrictor 2 apositioned proximal to (e.g., upstream) of the outflow port 4 p of thethoracic duct 4 being the only restrictor of the catheter 1, instead ofthe distal restrictor 2 b positioned distal to (e.g., downstream) of theoutflow port 4 p of the thoracic duct 4, may help prevent back flow fromthe subclavian vein 5 while providing the low pressure zone andbenefit(s) thereof.

In at least some embodiments, the catheter 1 can have a soft atraumatictip at its distal end 1 d that is tapered in a distal direction and thatis flexible. The soft atraumatic tip may facilitate smooth, safeintroduction of the catheter 1 into the vein 3. Exemplary materials fromwhich the atraumatic tip can be made include polyurethanes. The cathetermay additionally include a flexible extension similar to a guide wiretip and/or have a hydrophilic coating, each of which may furtherfacilitate smooth, safe introduction of the catheter 1 into the vein 3.

In at least some embodiments, the proximal restrictor 2 a can beconfigured to only partially occlude the vein 3 in which the catheter 1is positioned when the proximal restrictor 2 a in its activatedconfiguration. This partial occlusion may facilitate normal fluid flowthrough the vein 3 even when the proximal restrictor 2 a is in theactivated configuration. In embodiments in which the proximal restrictor2 a is configured to only partially occlude the vein 3 when in itsactivated configuration, the catheter 1 can, but need not, include theproximal inlet 8 p to facilitate fluid flow through the vein 3. Thepartial occlusion can be achieved in a variety of ways. For example, theproximal restrictor 2 a can have at least one lumen or hole formedtherethrough configured to allow fluid flow therethrough when theproximal restrictor 2 a is in the activated configuration. For anotherexample, a maximum diameter of the proximal restrictor 2 a in theactivated configuration can be less than a maximum internal diameter ofthe vein 3 in which the catheter 1 is positioned to allow fluid flowaround an exterior of the proximal restrictor 2 a.

In at least some embodiments, the catheter 1 can include at least onelumen or tube (not shown) configured to pass blood therethrough outsidethe patient's body and back into the patient. Such functionality mayallow for the monitoring of blood volume and performing hemofiltration.

In at least some embodiments, the catheter 1 can include one or moreradiopaque markers (not shown) configured to be visible using an imagingtechnique such as fluoroscopy. The one or more radiopaque markers can beon the catheter's shaft 7 at or near one or more features along theshaft 7, such as any or all of the inlet openings or any or all of therestrictors 2 a, 2 b. The one or more radiopaque markers may thusfacilitate proper positioning of the shaft 7 and/or features thereonwithin a vein. For example, prior to activation of the catheter'srestrictor(s) 2 a, 2 b, the position of the restrictor(s) 2 a, 2 bwithin the vein 3 can be verified by visualizing the one or moreradiopaque markers using an imaging system.

The first and second restrictors 2 a, 2 b are discussed with respect toFIG. 1 above as being balloons configured to inflate and deflate, butthe first and second restrictors 2 a, 2 b can have other configurations.For example, the first and second restrictors 2 a, 2 b can each includea stent configured to expand (corresponding to an activatedconfiguration) and constrict (corresponding to a relaxed configuration).The expandable/constrictable stents can have a variety ofconfigurations, as will be appreciated by a person skilled in the art.

FIG. 2 illustrates another embodiment of a catheter 100 that includes atleast one restrictor (not shown in FIG. 2 for clarity of illustration).The catheter 100 of FIG. 2 can generally be configured and used similarto that discussed above regarding the catheter 1 of FIG. 1, e.g.,include a shaft 102, a soft, distally-tapering atraumatic tip 104, adischarge opening 106, a proximal inlet opening 108, an impeller 110, adrive shaft 112 extending proximally to a motor (not shown), and adistal inlet opening 114. The motor in this illustrated embodiment isexternal, similar to the embodiment discussed above regarding thecatheter 1 of FIG. 1. The proximal inlet opening 108 in this illustratedembodiment is in the form of two opposed ovular openings formed througha sidewall of the shaft 102. The distal inlet opening 114 in thisillustrated embodiment is in the form of two opposed ovular openingsformed through a sidewall of the atraumatic tip 104 distal to the shaft102 (one of the openings is obscured in FIG. 2). The catheter 100 caninclude a bearing 116 just proximal to the impeller 110, which may helpstabilize the impeller 110 within the shaft 102.

FIGS. 3-6 illustrate another embodiment of a catheter 200 that includesat least one restrictor (not shown in FIGS. 3-6 for clarity ofillustration). The catheter 200 of FIGS. 3-6 can generally be configuredand used similar to that discussed above regarding the catheter 1 ofFIG. 1, e.g., include a shaft 202, a soft, distally-tapering atraumatictip 204, a discharge opening 206, a proximal inlet opening 208, animpeller 210, a motor 212, a drive shaft 214 extending between theimpeller 210 and the motor 212, and a distal inlet opening 216. Themotor 212 in this illustrated embodiment is an on-board motor configuredto be implanted with the catheter 200. Similar to the catheter 100 ofFIG. 2, the proximal inlet opening 208 in this illustrated embodiment isin the form of two opposed ovular openings formed through a sidewall ofthe shaft 202, and the distal inlet opening 216 in this illustratedembodiment is in the form of two opposed ovular openings formed througha sidewall of the atraumatic tip 204 distal to the shaft 202 (one of theopenings is obscured in FIGS. 3 and 4).

FIGS. 7-9 illustrate another embodiment of a catheter 300 that includesat least one restrictor 318, which in this illustrated embodimentincludes only one restrictor 318 that is located distal to an impeller310. The catheter 300 of FIGS. 7-9 can generally be configured and usedsimilar to that discussed above regarding the catheter 200 of FIGS. 3-6,e.g., include a shaft 302, a soft, distally-tapering atraumatic tip 304,a discharge opening 306, a proximal inlet opening 308, the impeller 310,an on-board motor 312, a drive shaft 314 extending between the impeller310 and the motor 312, and a distal inlet opening 316. The shaft 302includes multiple lumens extending therethrough, including a centrallumen 320 for the impeller 310 and the motor 312 and an inflation lumen322 for inflation/deflation of the restrictor 318, which in thisillustrated embodiment includes a balloon. FIGS. 7-9 show the restrictor318 in an activated configuration, which in this illustrated embodimentis an inflated configuration.

In at least some embodiments, a catheter including restrictors caninclude a flexible membrane to which the restrictors are appended andwhich enables fluid (e.g., blood flow) to bypass a low pressure zonedefined between the restrictors.

FIG. 10 illustrates one embodiment of an indwelling catheter system 10that can include a flexible membrane 28 and at least one restrictor 22,24, which are in the form of balloons in this illustrated embodiment. Asillustrated, the indwelling catheter system 10 includes an introducersheath 30 used to deploy a catheter 20 having a generally elongatetubular shape, with a circular or ovular cross-sectional geometry. Theindwelling catheter system 10 can include proximal end 10 p, which canbe configured to be placed outside of a patient's body, and distal end10 d, which can be configured for placement within a patient's vein.

The catheter 20 can have a single suction lumen 48 (see FIGS. 14 and 15)for communicating fluid out of the vein to an external pump, theflexible membrane 28 (which is tubular in this illustrated embodiment),and first and second restrictors 22, 24, which are attached to themembrane 28 and surround the membrane 28 and catheter 20. The flexiblemembrane 28 can be assembled to the catheter 20 (e.g., to the shaftthereof) in any of a number of ways to enable the flexible membrane 28to form an ovoid or a kidney shape upon expansion of the flexiblemembrane 28 (as a result of activating the restrictors 22, 24) so thatfluid can be transported from a position within the vein proximal to thefirst restrictor 22, through the low pressure zone within the vein, andto discharge the fluid at a point distal to the second restrictor 24.The flexible membrane 28 can be attached, e.g., bonded or welded, arounda partial portion (such as a non-zero portion that is less than 360° ofthe catheter shaft's circumference 50) or full portion (360° around thecatheter shaft's circumference 50) of the circumference 50 of thecatheter's shaft, such as in a range of about 10° to 360° of the shaft'scircumference 50. FIGS. 10A and 10B illustrate the flexible membrane 28attached to a partial portion around the catheter shaft circumference50. At least one inflation port 56 is in fluid communication with aninflation lumen (control lumen 42 discussed further below) for inflatingthe first restrictor 22 and is disposed on a surface of the flexiblemembrane 28 and will be underneath the first restrictor 22 attachedthereto, as discussed below. A second inflation port (not shown) is influid communication with at least one inflation lumen (control lumen 44discussed further below) for inflating the second restrictor 24 and isdisposed on a surface of the flexible membrane 28 and will be underneaththe second restrictor 22 attached thereto, as discussed below. As shownin FIG. 10B, which has a portion of the flexible membrane 28 removed forclarity of illustration, at least one suction port 26 is extendingthrough an external surface of the catheter 20 such that it is in fluidcommunication with a suction lumen 48.

Following attachment of the flexible membrane 28 to the catheter 20, therestrictors 22, 24 can be attached to the catheter 20. As shown in FIG.10C, the first restrictor 22 can be bonded or welded to an outer surfaceof the flexible membrane 28 over the inflation port 56 so that the firstrestrictor 22 surrounds the outer circumference 52, 54, of the catheter20 and the flexible membrane 28. As shown in FIG. 10D, edges of thefirst restrictor 22 can be flattened to extend beyond the collapsedballoon and bonded to the flexible membrane 28. The second restrictor 24can be attached to the catheter 20 similar to the first restrictor'sattachment to the catheter 20. In an alternate embodiment, as shown inFIG. 10E, a restrictor 22′ has at least one edge 52′ thereof foldedunder and bonded beneath the collapsible tube of the restrictor 22′. Oneor both of the first and second restrictors 22, 24 can be attached tothe catheter 20 similar to the attachment of the restrictor 22′ of FIG.10E.

FIGS. 10F-10H illustrate one embodiment of a method for manufacturing atorus-shaped restriction member 502 configured to be attached to acatheter shaft as discussed herein. As shown in FIG. 10F, a pattern 500is formed by a process such as blow molding or dip molding. For example,a slope of the mold pattern can be formed in a continuous shape withoutsharp corners or directional reversion. As shown in FIG. 10G, after therestriction member 502 is formed using the pattern 500, it is assembledonto a collapsible sleeve 510. During the assembly, two legs 504, 506 ofthe restriction member 502 are pushed towards each other and bondedtogether. The restriction member 502 maintains an opening 508 betweenthe legs 504, 506 to enable the formation or positioning of an inflationport in the catheter that will be used to inflate the restriction member502. As shown in FIG. 10H, after the legs 504, 506 are brought together,as explained above, a lower section of the restriction member 502 isinverted inward. The curvature of the restriction member 502 ismaintained in the opposite direction thereby maintaining materialcontinuity to form the restriction member 502, as illustrated.

The suction lumen 48 can accommodate the flow of fluid from the vein inwhich the catheter 20 is implanted to a pump external to the patient,when deployed, and the membrane 28 can enable fluid returned from thepump to bypass the portion of the vein occluded by the restrictors 22,24. As shown in FIGS. 11A, 11B, 14, and 15, the suction lumen 48 cancommunicate with the suction port 26, formed in an outer wall ofcatheter 20, and can extend to a proximal end of the catheter 20. Theproximal end of the catheter 20 can include a hub 34 which communicateswith discharge tubing (not shown) coupled to the pump external to thepatient (not shown) to communicate fluid withdrawn from within the lowpressure zone between the restrictors 22, 24 through the suction lumen48 of the catheter 20. Fluid present in the vein in which the catheter20 is implanted, and between the deployed restrictors 22, 24 of thecatheter 20, is drawn from the vein into the suction port 26 and intothe suction lumen 48 of catheter 20 so that it can be communicated tothe external pump (not shown) via the suction lumen 48 and the dischargetubing.

The tubing extending out of the pump (not shown) to return fluid to thecatheter system 10 can be coupled to the sheath 30 at a discharge port36 (see FIGS. 10, 12A, 12B, and 13). Fluid returned from the pump willenter the discharge port 36 and be discharged within the vein externalto the catheter 20. The pump can facilitate fluid movement from thecatheter 20 through the suction lumen 48 and into the discharge tubingthrough which it is communicated to the pump. The discharge port 36 canbe configured to connect to an end of the drainage tubing having itsother end in fluid communication with the pump. The discharge port 36can, as shown, include surface features formed thereon and extendingtherearound to facilitate its connection to the discharge tubing.

As shown in FIGS. 10, 10A, 11A, and 11B, the first restrictor 22 can bedownstream of (e.g., distal to) a proximal opening 28 p of the membrane28, and a distal opening 28 d of the membrane 28 can be downstream ofsecond restrictor 24. Thus, when the first and second restrictors 22, 24are activated or deployed to fully occlude the vein, the lumen of themembrane 28 can provide a bypass route for fluid (e.g., blood) returningfrom the external pump or otherwise flowing downstream within the veinexternal to catheter 20. In other words, even though the vein isoccluded by the restrictors 22, 24, blood and other fluid can flowthrough the lumen of the membrane 28 to flow from a position upstream of(e.g., proximal to) the proximal restrictor 22 to a position downstreamof the distal restrictor 24. Although the catheter 20 and the flexiblemembrane 28 are illustrated to be oriented in a side-by-siderelationship with respect to one another, they can be oriented in anyother suitable manner, including having one member disposed within theother member. Also, the catheter 20 can have any number of additionallumens, which can function, for example, as control lumens to facilitateactivation of the restrictors 22, 24 and/or to sense pressure at variouslocations within the vein in which the catheter 20 is disposed.

The catheter 20 can include a distal atraumatic tip 12 that canfacilitate placement of the catheter 20 into the vein of a patient. Thedistal atraumatic tip 12 can have an aperture such that the tip 12 has alumen extending therethrough. The lumen of the tip 12 can be configuredto allow passage of a guide wire through the tip 12. The catheter 20,including the flexible membrane 28 and the restrictors 22, 24, can beadvanced over the guide wire to be deployed from the sheath 30. Thelumen and the aperture can be sized to accommodate a standard guide wireof size such as about 0.014″, about 0.018″, about 0.035″, or about0.038″. In addition to or instead of the catheter 20 including thedistal atraumatic tip 12, the sheath 30 can include a distal atraumatictip to facilitate advancement of the sheath 30 having the catheter 20disposed therein to a location where the catheter 20 is to be releasedfrom (e.g., advanced distally out of) the sheath 30. The sheath's distalatraumatic tip can include a lumen to allow passage of a guide wirethrough the tip, as discussed above.

As shown in FIG. 11B, the catheter 20 can include one or more radiopaquemarkers 21 configured to be visible using an imaging technique such asfluoroscopy. As also shown in FIG. 11B, the catheter 20 can include oneor more sensors 23, which in this illustrated embodiment includes anoptic pressure transducer, located between the restrictors 22, 24 andhence within a low pressure zone created therebetween. The pressuretransducer 23 is configured to continually monitor pressure within thelow-pressure zone so pump function can be adjusted if necessary to keepthe pressure at a desired level (in a desired range of about 2 to 5mmHg, etc.) and at the location of the discharge lumen so internaljugular vein pressure can be monitored. The pressure transducer 23 isalso configured to provide CVP measurements when the restrictors 22, 24are deflated.

As shown in FIG. 12B, the catheter system 10 can include an eyelet 25configured to facilitate securement of the system 10 to a patient duringuse. For example, the eyelet 25 can be secured by a suture to thepatient's skin. The catheter shaft can be locked in position relative tothe sheath 30 using, for example, a Tuohy Borst valve, such that thecatheter 20 can be secured to the patient during use via the sheath 30.The eyelet 25 may thus be secured to the patient after the catheter 20has been advanced through the sheath 30 to be in a desired positionwithin the patient to help ensure that the system 10 is secured to thepatient with the catheter 20 in its desired position.

As shown in FIGS. 10, 12, and 13, the sheath 30 can include a pluralityof ports 32 a, 32 b, 32 c in fluid communication with respective ones ofa plurality of control lumens 42, 44, 46 within the catheter 20. Asshown in FIGS. 14-16, the first and second ports 32 a, 32 b respectivelycommunicate with the first and second control lumens 42, 44, which canbe configured to deliver fluid to the first and the second restrictors22, 24, respectively, to control the activation and deactivation of therestrictors 22, 24. The third port 32 c can communicate with the thirdcontrol lumen 46, which can communicate with an opening in the catheter20 for purposes of sensing a pressure within the vein, as discussedabove. The third control lumen 36 includes one or more pressure sensorsin this illustrated embodiment, but any one or more of the controllumens 42, 44, 46 can include one or more pressure sensors, to be usedfor sensing pressure at various locations along the vein in which thecatheter 20 is implanted, such as between the proximal and distalrestrictors 22, 24 and upstream of the proximal restrictor 22.

As shown in FIGS. 14 and 15, the suction lumen 48 is internal to thecatheter 20 and the flexible membrane 28 that is external to thecatheter 20 and is oriented in a side-by-side arrangement with respectto the catheter 20. The control lumens 42, 44, 46 can be disposed withinthe catheter 20, such as within the wall of the catheter 20, as shown.As indicated above, the cross-sectional arrangement of catheter 20 cantake various forms, and the relative positioning of the suction lumen 48and the control lumens 42, 44, 46 can vary. More or fewer suction lumens48 and control lumens 42, 44, 46 can be provided in the catheter 20. Forexample, one or more additional control lumens can accommodate a varietyof non-pressure sensors, as discussed above.

Sizes of the catheter 20, the sheath 30, and the flexible membrane 28can vary depending upon the catheter system's intended uses. Generally,the catheter 20 can have a length in the range of about 25 to 40 cm. Inaddition, the diameter can also vary, but suitable catheters willtypically be in the range of about 8 to 18 Fr. Other catheters describedherein can have a similar size, e.g., a length in the range of about 25to 40 cm and a diameter in the range of about 8 to 18 Fr. The sheath 30can have a length in the range of about 10 to 25 cm, can have aninternal diameter in the range of about 2.5 to 5.5 mm, and can have anexternal diameter in the range of about 3 to 6 mm. In one embodiment,the catheter 20 can have a diameter of about 8 Fr and the sheath 30 canhave a diameter of about 11 Fr. The flexible membrane 28 can have alength in the range of about 50 to 150 mm. A distance between the distalend of the sheath 30 and the proximal end of the flexible membrane 28can be up to about 100 mm. The diameter of the control lumens 42, 44, 46can vary depending upon the requirements of a given application. Thesuction lumen 48 can have a diameter in the range of about 1 to 4 mm,while pressure inflation lumens can have a diameter in the range ofabout 0.1 to 1 mm.

FIGS. 17A-17C illustrate one example of the catheter 20 implanted withina patient, in particular within a jugular vein 80 of the patient. FIG.17B also illustrates a location of the low pressure zone and illustratesfluid flow through the catheter 20 as indicated by two sets of arrowsinto and one set of arrows out of the catheter 20. FIG. 17C alsoillustrates one embodiment of a pump 27, a peristaltic pump (such as aperistaltic blood pump motor model DriveSure™ 48 VDC, Head model 520RL2,available from Watson Marlow), configured to pump fluid in and out ofthe catheter system 10 via the ports 32 a, 34. As shown, the firstrestrictor 22, which in this illustrated embodiment is positioned at aregion of the catheter 20 that is proximal to the suction port 26 andthat marks the proximal or upstream boundary of the low pressure zone,can be positioned proximal to (upstream of) a point at which thepatient's subclavian vein 82 enters the jugular vein 80. The secondrestrictor 24, which in this illustrated embodiment is positioneddistally of the first restrictor 22 and between the suction port 26 andthe distal end of the catheter 20, can be positioned distal to(downstream of) the point at which the subclavian vein 82 enters thejugular vein 80, and the second restrictor 24 can be in the patient'sinnominate vein 84. Alternatively, the catheter 20 can treat bothlymphatic ducts by placing the first restrictor 22 proximal to (upstreamof) the point at which the subclavian vein 82 enters the jugular vein 80and placing the second restrictor 24 distal (downstream of) to the pointat which both of the patient's innominate veins enters the subclavianvein 82. Alternatively, the second restrictor 24 can be positioned inthe subclavian vein 82.

The catheter 20 can be positioned with the jugular vein 80 as shown inFIGS. 17A and 17B in any of a variety of ways. For example, thepositioning can be conducted using a 12 Fr sheath 30 to puncture thevenous wall. The sheath 30 can be advanced into the vein 80 with thecatheter 20, the flexible membrane 28, and the restrictors 22, 24collapsed and contained therein. After insertion of the sheath 30, thecatheter 20 along with the flexible membrane 28 and the restrictors 22,24, can be advanced through the distal tip of the sheath 30 andpositioned downstream of the sheath 30. Alternatively, the sheath 30 canbe introduced first, and then the catheter 20 can be introduced by beingadvanced through the sheath 30. Regardless of whether the sheath 30 andthe catheter 20 are introduced sequentially or simultaneously, thecatheter 20 can be configured to be removed from the sheath 30 at anytime. If at any time throughout a procedure there might be a questionwith regards to the integrity of the catheter 20, the catheter 20 beingremovable with the sheath 30 remaining in place within the patientallows the catheter 20 to be replaced with a new one introduced into thesheath 30 or for the catheter 20 to be re-introduced into the sheath 30if the catheter's integrity is deemed acceptable.

The distal restrictor 24, when activated, isolates the incoming bloodflow from the subclavian and jugular veins 82, 80 from the blood flow ofthe innominate vein 84 and ensures that all incoming blood is directedto the pump 27. The proximal restrictor 22, when activated, isolates theblood flow from the jugular vein 80 and ensures that all blood flow froma position upstream of the proximal restrictor 22 is transported throughthe flexible membrane 28. The pump is activated to maintain the jugularand innominate vein pressure and thus the nominal blood flow. Theproximal restrictor 22, when activated, directs the blood flow from thejugular vein 80 and from the discharge port 36 within the sheath 30 downto the innominate vein 84. Actuation of the pump helps to create a lowpressure zone in the vicinity of the junction of the jugular vein 80 andthe subclavian vein 82 by withdrawing fluid in this region,recirculating it through the pump, and discharging the fluid upstream ofthis region through the sheath 30. Because the outflow of the thoracicand lymphatic ducts is located in this region, the lower pressure willfacilitate drainage of lymphatic fluid.

The catheter 20 can be implanted in the jugular vein 80 as shown inFIGS. 17A and 17B in any of a variety of ways. FIGS. 18-20 illustrateone embodiment of implanting the catheter 20 can be implanted in thejugular vein 80. The catheter 20 can be similarly implanted in anothervein, and other catheters described herein can be implanted in a veinsimilar to that discussed with respect to FIGS. 18-20.

FIGS. 18 and 19 illustrate the indwelling catheter system 10 (only adistal portion thereof is shown in FIG. 18) in an initial configurationin which the catheter 20 is disposed within the sheath 30 in acompressed configuration. In the initial configuration, the sheath 30can have the catheter shaft 20 positioned therein, encircled by acompressed flexible membrane 28 further surrounded by compressedrestriction members 22, 24.

A distal portion of the indwelling catheter system 10, e.g., a distalportion of the sheath 30, in the initial configuration can be insertedinto the jugular vein 80 of the patient, which is the right internaljugular vein in this illustrated embodiment. A proximal portion of theindwelling catheter system 10, e.g., a portion including the ports 32,34, 36, can remain outside the body of the patient to facilitate accessto the ports 32, 34, 36. With the distal portion of the catheter system10 at the target site (e.g., within the vein in which the catheter 20 isto be implanted), the catheter 20 can be advanced out of the sheath 30,as shown in FIG. 20, such that a proximal portion thereof is positionedwithin the jugular vein 80 and a distal portion thereof is positionedwithin the SVC 84. The suction port 26 disposed between the first andsecond restriction members 22, 24 enables suction of blood depositedwithin the low pressure zone from the subclavian vein 82 and from theinnominate vein 84. Such arrangement enables drainage of both thepatient's right lymphatic duct and thoracic duct. After positioning ofthe catheter 20 within the patient, the first and second restrictors 22,24 can be expanded, e.g., moved from their relaxed configuration totheir activated configuration, as shown in FIGS. 17A and 17B. Theexpansion of the restrictors 22, 24 also expands the flexible membrane28, e.g., moved the flexible membrane 28 from a relaxed configuration toan activated configuration. As mentioned above, the restrictors 22, 24can be expanded simultaneously or sequentially. As mentioned above, theexpansion of the restrictors 22, 24 isolates a portion of the vein 80 inwhich the catheter 20 is deployed from a surrounding area, and, thus, anarea (e.g., a low pressure zone) proximate to the thoracic duct isisolated and fluid can be removed via the suction port 26 positioned onthe catheter 20 located within the isolated area.

The catheter system 10 discussed above is configured to pump blood outof a patient's body and back into the body. A catheter system caninstead include an impeller, such as in the catheter embodiments ofFIGS. 1-6, such that blood need not be pumped out of and back into apatient's body and features of the catheter system 10 related theretoneed not be included (e.g., a pump, a discharge port, and related tubingneed not be included). The catheter system including an impeller canotherwise be similar to the catheter system 10, e.g., include a flexiblemembrane, include a sheath, etc.

The catheters described herein can be used in a variety of surgicalmethods, including surgical methods for treating pulmonary edema. Themethod can include verifying a location of the patient's thoracic ductand/or the patient's lymphatic duct, which can help a surgeon and/orother medical professional involved in performing a surgical procedurethat includes implanting the catheter verify that the restrictor(s) ofthe catheter are implanted in the correct location within the patient.The verification can be performed in any of a variety of ways, as willbe appreciated by a person skilled in the art, such as by using animaging technique such as echo or fluoroscopy. In an exemplaryembodiment, the verification can include advancing a set of pig tailedwires into the patient's subclavian or jugular veins and advanced towarda junction of the jugular and subclavian veins. Once one of the pigtailed wires enters the lymphatic duct or the thoracic duct, that one ofthe pig tailed wires can open itself inside the duct it entered, e.g.,due to a default expanded configuration of the wire. The pig tailedwires can include, for example, a default expanded circle size of 4 cm.The location of the entered duct can be verified using an imagingtechnique that visualizes the expanded wire therein.

The verification can occur after the implantation of the catheter suchthat the implanted location of the catheter can be determined in view ofthe verification and adjusted if need be in view of the verification.Additionally or alternatively, the verification can be performed priorto the implantation of the catheter. Similarly, the verification can beperformed prior to and/or after the restrictor(s) are moved from therelaxed configuration to the activated configuration to verify theposition(s) of the restrictor(s), and the verification can be performedprior to and/or after one or more sensors are implanted in the to verifythat the sensor(s) are desirably positioned. As discussed above, thesensor(s) in some embodiments are not implanted and are instead locatedoutside the patient's body, and/or at least one sensor is implanted andat least one sensor is located outside the patient's body. Variousembodiments of positioning tubes such as catheters is further describedin U.S. Patent Publication No. 2015/0343136 entitled “System And MethodFor Treating Pulmonary Edema” filed Feb. 19, 2015, which is herebyincorporated by reference in its entirety.

With the catheter implanted, the restrictor(s) in the activatedconfiguration, and, if being used in the system, the sensor(s)positioned, fluid flow can be controlled with the pump. The control cangenerally occur as described above. In at least some embodiments,controlling the pump can include continuously running the pump. In atleast some embodiments, controlling the pump can include periodicallyrunning the pump. In periodically running the pump, the pump can defaultto an idle state in which the pump is not pumping fluid. For example, inresponse to receipt of a user input requesting pumping, e.g., input by auser to an I/O device in electronic communication with the pump via acontroller, input wirelessly to the pump, etc., the pump can be actuatedso as to run and pump fluid. The pump can continue pumping untiloccurrence of a stop condition. Examples of the stop condition include apredetermined amount of time passing after the pump starts running and asecond user input being received that requests pumping to stop. Inresponse to the stop condition occurring, the pump can be actuated toreturn to its idle state. For another example, in response to sensing aparticular parameter value (e.g., a particular pressure value, etc.)with one or more sensors, the pump can be actuated so as to run and pumpfluid or the pump can be stopped so as to stop pumping fluid. Theparameter can continue being measured with the one or more sensors,thereby allowing the pump to be controlled in real time in response tomeasured values.

In at least some embodiments, a control module can be configured tocontrol the operation of a system including a catheter. For example, fora system configured to treat pulmonary edema, the system can include acontrol module to receive information from sensor(s) of the system, toactivate restrictor(s) of the system, and adjust a flow rate of a pumpof the system. Upon receiving information from the sensor(s), thecontrol module can be configured to actuate the pump function. Thecontrol module can further be configured to process information receivedfrom the sensor(s) to alter restriction volume, such as an inflationamount of each of the system's one or more restrictors. In at least someembodiments, the system can include a plurality of sensors and thecontrol module can be configured to receive information from at leastone of the sensors regarding pressure within a jugular vein of apatient, information from at least one of the sensors regarding pressureat the bifurcation of the patient's jugular and subclavian veins, andinformation from at least one of the sensors regarding pressure at thepatient's innominate vein. Embodiments of a control module include themotor/controller 9 of FIG. 1, a control module 600 of FIG. 21, a controlmodule of FIG. 22, and a control module 826 of FIG. 26.

The control module 600 of FIG. 21 includes a computer (e.g., a PC, etc.)602, a controller 604 in the form of an embedded real time controller, asafety relays board 606, a pump 608 in the form of a peristaltic pump,pump pressure sensors 610 that include a pump inlet pressure sensor anda pump outlet pressure sensor, catheter pressure sensors 612 thatinclude a first catheter pressure sensor configured to be positioned ina jugular vein of a patient and a second catheter pressure sensorconfigured to be positioned in a subclavian vein of the patient, an airbubble detector 614, an alarm notification mechanism 616 in the form ofan alarm buzzer, a fan 618 configured to provide cooling for safety, anelectrical inlet 620, and a power supply 622 in the form of an AC to DCpower supply. The control module 600 can also include a drip chamber(not shown) configured to allow gas (e.g., air) to rise out of bloodflowing through the control module 600 before the blood returns to thepatient to facilitate patient safety. The computer 602 is shown as partof the control module 600 in this illustrated embodiment, but thecomputer 602 can be a separate component from the control module 600 andinstead be coupled thereto electronically (wired or wireless).

The computer 602 is configured to act as a control panel for a user tomonitor patient and pump parameters so the user can make decisionsregarding patient care. The computer 602 includes a user interface on adisplay thereof to facilitate providing of the parameters to the user.The computer 602 is configured to provide on the user interfaceidentified safety-related concerns, such as air bubbles detected by theair bubble detector 614, and/or to cause the notification mechanism 616to provide notification of the identified safety-related concerns to theuser, such as by buzzing the alarm buzzer, by illuminating a lightcoupled to the control module 600, by sending an electronic message suchas an email or a text message to the user, by showing a message on thecomputer's display, etc.

The computer 602 is configured to receive real time information fromvarious components of the control module 600, via the real timecontroller 604, which may facilitate control of the catheter system thatincludes the control module 600, facilitate providing notice to a userof system functionality, and/or facilitate collection of data for lateranalysis for patient treatment purposes. The user notification allowsthe user to take one or more corrective actions to address the subjectmatter of the notification, such as adjusting a speed of the pump 608,deflating restrictor(s) of the catheter system to allow catheterremoval, powering off the control module 600, etc. For example, thecomputer 602 receives real time pump outlet pressure information fromthe pump outlet pressure sensor 610 to allow the computer 602 todetermine whether the pump outlet pressure is within a pre-programmedacceptable safe range and, if not, to adjust a speed of the pump 608 tourge the pump outlet pressure to be within the safe range and/or cause auser notification to be provided indicating a possible unsafe pressuresituation. For another example, the computer 602 receives real time pumpinlet pressure information from the pump inlet pressure sensor 610 todetermine whether the pump inlet pressure is within a pre-programmedacceptable safe range and, if not, to adjust a speed of the pump 608 tourge the pump inlet pressure to be within the safe range and/or cause auser notification to be provided indicating a possible unsafe pressuresituation. For yet another example, the computer 602 receives real timejugular vein pressure information from the first catheter pressuresensor 612 to determine whether it is within a pre-programmed acceptablesafe range and, if not, to adjust a speed of the pump 608 to urge thejugular vein pressure to be within the safe range and/or cause a usernotification to be provided indicating a possible unsafe pressuresituation. For still another example, the computer receives subclavianvein pressure information from the second catheter pressure sensor 612to determine whether it is within a pre-programmed acceptable safe rangeand, if not, to adjust a speed of the pump 608 to urge the subclavianvein pressure to be within the safe range and/or cause a usernotification to be provided indicating a possible unsafe pressuresituation. For another example, the computer 602 receives air bubbleinformation from the air bubble detector 614 to determine if blood beingpumped by the pump 608 includes an amount of air bubbles over apredetermined threshold level and, if so, adjust a speed of the pump 608to reduce the level of air bubbles and/or cause a user notification tobe provided indicating a possible thrombosis risk due to air bubblepresence. For yet another example, the computer 602 receives pumprotation information from a pump tachometer coupled to the pump 608 todetermine whether the pump 608 is operating within its presetoperational limit and, if not, to adjust a speed of the pump 608 to bewithin its preset operational limit and/or cause a user notification tobe provided indicating a possible pump failure situation. For anotherexample, the computer 602 receives fan rotation information from a fantachometer coupled to the fan 618 to determine whether the fan isrotating above a predetermined threshold and, if so, to adjust a speedof the fan 618 to be within its preset operational limit and/or cause auser notification to be provided indicating a possible overheatingsituation.

In an exemplary embodiment, the computer 602 is configured to providethe user notification without causing any automatic corrective action tobe performed in order to increase user control. In other embodiments,the computer 602 is configured to automatically cause a correctiveaction to be performed for certain conclusions drawn from receivedinformation, namely conclusions that pose an imminent risk to patientsafety and/or control module failure, such as automatically reducing aspeed of the pump 608 if it is determined to be running above itsmaximum safe limit or stopping the pump 608 if too many air bubbles aredetected, and to not automatically cause a corrective action to beperformed for all other conclusions drawn from received information.

FIG. 22 illustrates one embodiment of the control module 600 of FIG. 21.The control module includes a housing 700 having electronic componentsdisposed therein (e.g., the controller 604, the safety relays board 606,the alarm notification mechanism 616, the fan 618, the power supply 622,etc.). Attached to the housing 700 are a pump 702, pump pressure sensorsthat include a pump inlet pressure sensor 704 and a pump outlet pressuresensor 706, a drip chamber 708, an air bubble detector 710, a catheterpressure sensor inlet 712 configured to couple to the catheter pressuresensors, an inlet blood line clamp 714 configured to clamp to an inlettube of a blood line through which blood flows from the patient to thepump 702, and an outlet blood line clamp 716 configured to couple to anoutlet tube of the blood line through which blood flows from the pump702 to the patient. The blood line can include any of a variety oftubing sets, as will be appreciated by a person skilled in the art. Thecontrol module of FIG. 22 does not include a computer and is configuredto electronically couple to a computer.

A control module configured to control the operation of a systemincluding a catheter can include one or more feedback loops to adjustperformance of the system to create and maintain a low pressure zonewhile lymphatic fluid is cleared in a context of a system configured totreat pulmonary edema in a patient. FIGS. 23-28 illustrate oneembodiment of a process to create a low pressure zone and transportfluid from a low pressure zone back into the venous system of a patientin a context of a system configured to treat pulmonary edema in apatient.

As shown in FIG. 23, a distal portion of a catheter system 800 isintroduced into a patient. A distal end of a sheath 802 is positionedwithin a jugular vein 804 of the patient proximal to a subclavian vein806 of the patient and thoracic duct 808 outlet. A distal end of acatheter 814, e.g., an atraumatic distal tip 816 thereof, just beyondthe distal end of the sheath 802 is also positioned within the jugularvein 804 proximal to the subclavian vein 806 and the thoracic duct 808outlet. A guidewire 810 extending through the sheath 802 and thecatheter 814 extends distally beyond the sheath's distal end and thecatheter's distal end and extends distally past the subclavian andjugular bifurcation to be in an innominate vein 812 of the patient.Blood continues to flow normally from the jugular vein 804 into theinnominate vein 812 and from the subclavian vein 806 into the innominatevein 812, with the blood flowing around the sheath 802 and catheter 814.A pressure at the subclavian and jugular bifurcation at this point isshown in FIG. 23 as being at 15 mmHg.

As shown in FIG. 24, the catheter 814 is then advanced distally from thesheath 802 over the guidewire 810 to extend across the subclavian andjugular bifurcation. A proximal restrictor 818 of the catheter 814 ispositioned proximal to (upstream of) the subclavian and jugularbifurcation, and hence proximal to the thoracic duct 808 outlet, and adistal restrictor 820 of the catheter 814 is positioned distal to(downstream) of the subclavian and jugular bifurcation, and hence distalto the thoracic duct 808 outlet. The proximal and distal restrictors818, 820 are collapsed. A flexible membrane 822 of the catheter 814 isalso collapsed. Blood continues to flow normally from the jugular vein804 into the innominate vein 812 and from the subclavian vein 806 intothe innominate vein 812, with the blood flowing around the sheath 802and catheter 814.

As shown in FIG. 25, the restrictors 818, 820 and the flexible membrane822 are then expanded. Blood now flows from the jugular vein 804 intothe flexible membrane 822 and flows therethrough across the subclavianand jugular bifurcation into the innominate vein 812. Blood is now notflowing from the subclavian vein 806 into the innominate vein 812.

As shown in FIG. 26, a pump 824 of a control module 826 is activated(e.g., is turned on, as indicated by an illuminated power light shownstanding alone in FIG. 26 to allow it to be visible in FIG. 26) tosuction blood into proximal and distal suction ports 828, 830 of thecatheter 814 that are located between the restrictors 818, 820. Thesuctioning draws the blood into the catheter 814 (e.g., into thecatheter shaft's inner lumen) and toward the pump 824, and thesuctioning reduces the pressure at the subclavian and jugularbifurcation. A pressure at the subclavian and jugular bifurcation atthis point is shown in FIG. 26 as being at 4 mmHg, which is reduced fromthe previous 15 mmHg value at the subclavian and jugular bifurcation.The pressure is measured at the subclavian and jugular with a firstpressure sensor 832 of the catheter 814. The pressure proximal to theproximal restrictor 818 is shown as 15 mmHg in FIG. 23. The pressureproximal to the proximal restrictor 818 is measured with a secondpressure sensor 834 of the catheter 814 (see FIG. 26A). A low pressurezone has thus been formed between the restrictors 818, 820. Blood nowflows from the jugular vein 804 into the flexible membrane 822 and flowstherethrough across the subclavian and jugular bifurcation into theinnominate vein 812. Blood now flows from the subclavian vein 806 intothe catheter 814.

As shown in FIG. 27, blood returns to the sheath 802 from the pump 824to flow into the flexible membrane 822 proximal to the proximalrestrictor 818 and across the subclavian and jugular bifurcation intothe innominate vein 812. Blood now flows from the jugular vein 804 intothe flexible membrane 822 and flows therethrough across the subclavianand jugular bifurcation into the innominate vein 812. Blood now flowsfrom the subclavian vein 806 into the catheter 814 and returns to thepatient via the sheath 802. FIG. 28 shows the low pressure zone with apressure of 4 mmHg and pressures on either side thereof as being at 15mmHg.

The blood flow of FIGS. 27 and 28 remains until the pump 824 isdeactivated (e.g., turned off) and/or the restrictors 818, 820 arecollapsed. The control module 826 functions as discussed herein,allowing data for various parameters to be collected and analyzed.

FIG. 29 illustrates another embodiment of a process 400 to create a lowpressure zone and transport fluid from a low pressure zone back into thevenous system of a patient in a context of a system configured to treatpulmonary edema in a patient. At step 402 of the process 400 a controlmodule acquires baseline pressure(s), such as a jugular pressure and abaseline bifurcation pressure. The baseline bifurcation pressure isacquired, for example, by the pressure sensors of a catheter of thesystem when the one or more pressure sensors are out of the system'ssheath. Once the catheter is taken out of the sheath, the pressuresensors can read baseline pressure within the patient. After thebaseline pressure is read, the catheter can be advanced to its finalposition within the patient.

The control module at step 404 of the process 400 measures a diameter ofthe patient's jugular vein and a diameter of the patient's innominatevein. The diameters can be measured, for example, by a correlationbetween a volume that is inflated into the catheter's restrictionmembers and the pressure reading at the catheter's pressure sensors.When the distal one of the restriction members (e.g., the restrictionmember positioned in the patient's innominate vein) is inflated to thelevel of the vein in which it is positioned suddenly there is an abruptincrease pressure, which is read by the catheter's pressure sensors(e.g., one pressure sensor in the patient's jugular vein and anotherpressure sensor in the patient's innominate vein). This abrupt increaseindicates that the vessel diameter has been achieved. From the amount ofvolume that was inflated, the diameters are now known since there existsa 1:1 correlation between the volume and diameter curve for therestriction members.

At step 406 of the process 400 the control module selects an inflationsize of the system's restrictor(s) and can calculate a volume of therestrictor(s). In the distal one of the restriction members, theinflation size is measured as described above, for example. In theproximal one of the restriction members (e.g., the restriction memberpositioned in the patient's jugular vein), the inflation size isdetermined, for example, using a visualization technique such asultrasound to measure the correct diameter, as it can be easilyvisualized. At step 408 of the process 400, a target bifurcationpressure is calculated by the control module. The target pressure istaken to be, for example, over 50% reduction from the baseline pressure.

At step 410 of the process 400, a catheter of the system is placedwithin the patient, for example by being distally advanced out of asheath as discussed above. At step 412 of the process 400, a flow rateof a pump of the system equals zero, and a volume of each of thesystem's one or more restrictors equals zero. Next, at step 414 of theprocess 400, the control module causes the restriction member(s) to bedeployed (e.g., inflated) to accommodate the vein size. The restrictionmember(s) are inflated to the inflation size selected above.

At step 416 of the process 400, the control module determines if thebaseline bifurcation pressure (Pb) is greater than the targetbifurcation pressure (Pbt). If the baseline bifurcation pressure isgreater than the target bifurcation pressure, the control increases thepump flow at step 418 of the process 400. The process 400 then revertsback to repeat step 416 to re-measure the target bifurcation pressure.With two pressure sensors (in the innominate and jugular veins in thisexample) that work simultaneously, this process 400 is accurate and realtime. If the baseline bifurcation pressure is not greater than thetarget bifurcation pressure, then the process 400 proceeds to step 420in which the control module determines if the baseline bifurcationpressure is less than the target bifurcation pressure minus a safetydelta (SD). The safety delta comes from different scenarios. The targetbifurcation pressure is typically in a range of 0 to 5 mmHg. However, ifthe baseline pressure is very high (e.g., above about 15 mmHg) it canalso be considered a successful treatment if the target pressure isabove the typical range, e.g., is in a range of about 5 to 7 mmHg.Therefore, for each baseline pressure there is a target pressure whichcan be more than 50% of the baseline pressure. If the baselinebifurcation pressure is less than the target bifurcation pressure minusthe safety delta, the process 400 proceeds to step 422 to reduce theinitial pump flow, and the process 400 re-measures the targetbifurcation pressure at step 416. If the baseline bifurcation pressureis not less than the target bifurcation pressure minus the safety delta,the process 400 advances to step 424 and a working system condition isachieved.

One skilled in the art will appreciate further features and advantagesof the invention based on the above-described embodiments. Accordingly,the invention is not to be limited by what has been particularly shownand described, except as indicated by the appended claims. Allpublications and references cited herein are expressly incorporatedherein by reference in their entirety.

What is claimed is:
 1. A catheter for treatment of edema in a subject,the catheter comprising: a hollow body; an expandable membrane along anoutside of a portion of the hollow body, the expandable membranecomprising a proximal restrictor and a distal restrictor, each coupledto an outside of the expandable membrane and spaced apart from eachother to thereby form a channel through the expandable membrane whenexpanded, wherein expansion of the proximal restrictor and the distalrestrictor causes expansion of the membrane; and at least one inletalong a side wall of the expandable membrane between the proximalrestrictor and the distal restrictor.
 2. The catheter of claim 1,comprising a plurality of inlets along the side wall of the expandablemembrane between the proximal restrictor and the distal restrictor. 3.The catheter of claim 1, wherein the hollow body comprises an outletexternal to the subject, the outlet configured to be coupled to a pump.4. The catheter of claim 1, wherein the catheter is sized to fit withinan introducer sheath.
 5. The catheter of claim 1, wherein the distalrestrictor and the proximal restrictor each comprises an inflatableballoon coupled to an inflation lumen extending along the hollow body.6. The catheter of claim 5, wherein inflation of the balloons causes theexpandable membrane to assume an expended configuration.
 7. The catheterof claim 1, wherein the inlet is disposed approximately midway betweenthe proximal and distal restrictors.
 8. The catheter of claim 1, whereinthe distance between the proximal and distal restrictors is betweenabout 1 cm and about 15 cm.
 9. The catheter of claim 1, furthercomprising one or more pressure sensors.
 10. The catheter of claim 9,wherein a first pressure sensor is located between the proximal anddistal restrictors and a second pressure sensor is located upstream ordownstream of the expandable membrane.
 11. A method of treating edema ina subject, the method comprising: positioning a catheter within ajugular vein of a patient so that proximal and distal restrictors on thecatheter flank a lymphatic outflow duct; deploying the proximal anddistal restrictors to form a bypass channel, which bypass channel is anextendable membrane that is expanded as a result of deployment of theproximal and distal restrictors, wherein the proximal and distalrestrictors are each coupled to an outside of the extendable membrane;and drawing fluid into the catheter through an inlet located between theproximal and distal restrictors.
 12. The method of claim 11, wherein theproximal and distal restrictors each comprises an inflatable balloon.13. The method of claim 11, further comprising flowing blood from thejugular vein through the bypass channel.
 14. The method of claim 13,wherein the flow of blood through the suction lumen decreases pressureat the lymphatic outflow duct.
 15. The method of claim 11, furthercomprising removing the fluid from the patient and returning the fluidto the patient, wherein the fluid comprises blood and lymphatic fluid.16. The method of claim 15, wherein the fluid is bypassed from thesuction to discharge lumen by operating a pump located outside of thepatient.
 17. The method of claim 16, further comprising monitoring, viaone or more pressure sensors on the catheter, pressure within thejugular vein or at the lymphatic outflow duct.
 18. The method of claim17, further comprising maintaining a low pressure zone by changing rpmof the pump as a function of pressure sensed in the patient.
 19. Themethod of claim 16, further comprising reducing pressure near thelymphatic outflow duct to a pressure at or below 6 mmHg.